Ofcourse, Scotland going its own way would leave England with a nasty hole in its national defence.... England would need to find a new home for its Trident Fleet. It would need to find replacements for some of the best infantry and cavalry regiments (second only to the regiments from Norn Iron ofc!
) in the Army, and it would loose the Crab Airways bases north of the boarder.
So wanting to get shot of Scotland, Wales and Northern Ireland my suit your Little Englander tendencies Ramrod. But in truth is highly unlikely to be practical.